To the right is a diagram of the basic
structure of the nail. Some of the more important anatomical terms
are:

Bed --
the portion of skin upon which the nail rests.

Eponychium --
the skin at the base of the nail. It's also called the
"proximal nail fold", as it is labeled in the diagram.
Hyponychium -- the skin beneath the tip of
the nail.

Lunula -- the white half-moon-shaped
structure near the base of the nail.

Matrix --
another word for the nail root.

Additionally, there are many different tongue-twisting terms to
describe nail conditions, so we thought we'd provide a glossary of terms
you may hear relating to the nails.

For more information on specific nail conditions,
please visit our web page on information about nail
disorders and their treatment.

The glossary is in alphabetical order,
but I'll start by mentioning that Onyx
is the Greek word for nail, and Unguis is
the Latin word for nail. Knowing this makes it easier to see the
derivation of many of the words below, many of which contain the prefix
"onych-" or "ungui-".

Anonychia -- the
absence of a nail. This word comes from the Greek prefix "a-", meaning
"without", and "onych-" meaning "nail".

Avulsion -- the removal
of the nail. May be done in a manner to allow the nail to grow back, or in
a manner to prevent the regrowth of the nail.

Granuloma -- overgrowth
of highly vascular (good blood supply) soft tissue, typically caused from
chronic irritation of a nail, such as an ingrown nail. (You can see
an example of a granuloma in the reddish tissue on the sides of the nail
pictured under the heading of ingrown nails.)

Hangnail -- a small
loose flap of skin next to a nail plate.

Hapalonychia -- soft
nails. Same as onychomalacia.

Incurvated Nails --
nails which are curved and dig into the side of the skin, but without breaking
the skin and being truly ingrown.

Ingrown Nails -- nails
which are digging into the skin, thereby causing a break in the skin.
Ingrown nails are characterized by inflammation and because of the break in the
skin, they are frequently infected. We have a separate web page that
discusses ingrown
nails, and another web page that discusses nail
surgery. (See "onychocryptosis",
"onychoincurvatum",
"paronychia"
and "granulation tissue"
for related terms.)

Koilonychia--
spoon-shaped nails.

Leukonychia-- white
discoloration of the nail, frequently an early sign of fungal infection.
When the discoloration is present as a line or series of lines as it is
in the picture to the right, it is known as "leukonychia striata".
When the white discoloration is present as small white spots or dots, it
is known as "leukonychia punctata".
Usually caused from trauma to the nail.

Onych-,
onycha- or Onycho-
is a prefix meaning "nail". It comes from the Greek word for
nail, "Onyx".

Onychalgia -- pain of
the nail.

Onychauxis --
thickening of the nail, often as a result of fungus (a condition known as "onychomycosis"
or "tinea unguium").

Onychectomy --
Surgical removal of a nail.

Onychocryptosis --
another word for an ingrown nail. We have a
separate web page that discusses ingrown
nails, and another web page that discusses nail
surgery.

Onychodystrophy --
generalized term for any malformation of the nail.

Onychogryphosis
-- severe overgrowth of nails to the extent that the nails have the appearance
of a ram's horn. (See picture to the right.)

Onychoheterotopia --
a nail in an abnormal location.

Onychoincurvatum --
an incurvated nail, without necessarily being ingrown.